Method and Production Line for Manufacturing Metal Strips Made of Copper or Copper Alloys

ABSTRACT

Disclosed are a method and a production line for manufacturing metal strips made of copper or copper alloys by means of casting and rolling. In order to lower the investment cost and operating expenses therefor, the melt ( 2 ) is cast into a copper strip ( 4 ) in a vertical and/or horizontal continuous strip casting process ( 3 ), and the hot copper strip ( 4 ) is cleaned by milling ( 5 ) the top and bottom face ( 5   a   , 5   b ) thereof, is subjected to a cold rolling process ( 6 ) and is prepared for shipping, or is subjected to an inspection ( 12 ) and then prepared for shipping after being annealed ( 7 ), pickled ( 8 ), washed ( 9 ), dried ( 10 ), and optionally temper rolled ( 11 ).

The invention concerns a method and a production line for producing metal strip from copper or copper alloys by casting and rolling.

Until now, metal strip of this type made of soft metals, such as copper or copper alloys, has been produced by casting in slabs (DE 692 22 504 T2). After it has been cooled, the slab must be reheated and rolled out to the required thickness in a hot rolling process. The hot rolling is followed by milling of the upper and lower surfaces, inspection, and coiling into a coil. The metal strip is unwound from the coil and passed through a reversing mill. After a cold rolling operation, it is coiled into a coil and in this form is annealed in a box annealing installation for microstructural refinement or is continuously annealed in uncoiled form. It is then pickled, washed, dried, and temper rolled, and the surface is reinspected before the strip is coiled.

The operating costs to be expended for this and the investment costs for new construction and plant design with available useful floor space are basically very high. Metal strip made of copper or copper alloys are cast and rolled in horizontal casting processes at, for example, 15-20,000 t/year and with significantly lower investment costs.

Increased capacity, which is presently demanded by the market (30,000 to 70,000 t/year), can no longer be economically achieved with the present cost structure.

The objective of the invention is nevertheless to realize the increased capacity that is being demanded in combination with lower operating costs and reduced plant investment costs.

In accordance with the invention, the stated objective is achieved by casting the melt into copper strip in a vertical and/or horizontal continuous strip casting process, cleaning the copper strip by milling its upper side and underside, subjecting it to a cold rolling process, and preparing it for shipment, or first annealing, pickling, washing and drying it, and possibly subjecting it to a temper rolling step, and then inspecting it and preparing it for shipment. The advantages are that a slab casting installation, heating of the slab to rolling temperature, and hot rolling are completely eliminated. Furthermore, it is advantageous that the cold rolling process can be flexibly adapted to the planned production amounts, for example, by virtue of the fact that the cold rolling can be operated at optimum strip temperature on the delivery side.

In one embodiment, stacks of sheets can be produced from inspected coils by cutting the copper strip to length.

In another embodiment, coilable narrow copper strips can be produced from inspected coils by slitting the copper strip.

It is advantageous to effect temperature control during cold rolling by lubricating the copper strip with oil on the run-in side and cooling it with cold or cryogenic inert gases on the runout side. Various media can be used for cooling.

In this regard, it is advantageous if the set-point assignment for the rolling parameters is set to a maximum strip temperature of 120° C. In this way, the parameters (actual values) for casting and milling can be connected to the rolling process.

The method can be still further improved if the coils of copper strip that have been cold rolled under temperature control to final strip thickness are further refined in their microstructure either in a box annealing installation in the form of a coil or in a continuous annealing operation and then pickled, washed and dried, subjected to a surface inspection, and then further processed in coil form.

The production line for producing metal strip from copper or copper alloy with at least a melting installation, a casting installation, and a rolling installation is preferably designed for cold forming from 23 mm to 0.2 mm copper strip thickness.

To achieve the stated objective with respect to the equipment, it is proposed that the melting installation be followed in succession in the direction of production by at least one vertical continuous strip casting installation and/or one horizontal continuous strip casting installation, a milling installation immediately downstream, a strip uncoiler, a cold rolling installation, a strip coiler, and an annealing installation. A casting installation for slabs, which cool and then must be reheated to rolling temperature in a furnace, and a hot rolling mill itself are completely eliminated. This means not only lower capital expenditure for the construction of the production line but also lower operating expenses (lower repair costs and shorter repair times) and at the same time greater productivity of the plant.

Additional advantages are realized in the further course of the production line:

The cold rolling installation consists of a reversing mill.

The milling installation is located immediately downstream of the vertical continuous strip casting installation. It is advantageous that the copper strip runs directly into the next installation.

The vertical continuous strip casting installation, the milling installation, and the reversing mill follow one another in immediate succession. The copper strip runs into the following installation without interruption.

The cold rolling installation consists of a tandem mill.

The vertical continuous strip casting installation, the milling installation, and the tandem mill follow one another in immediate succession. The copper strip runs from installation to installation without interruption.

To realize higher rolling capacities, it is advantageous for two parallel upstream vertical continuous strip casting installations and milling installations to be assigned to the tandem mill.

To realize a higher casting capacity relative to the rolling installation, one vertical and one horizontal continuous strip casting installation, each with a milling installation installed immediately downstream of it, are installed upstream of the tandem mill.

When there are two casting installations, the production line is designed in such a way that with two parallel-casting vertical continuous strip casting installations, a reversing mill follows each milling installation.

In another combination for casting/milling and rolling, parallel-producing vertical and horizontal continuous strip casting installations are each followed by a reversing mill.

For all combinations of the production line, it is provided that the annealing installation consists either of a box annealing installation for coils or of a continuous annealing installation in the form of a strip floating furnace.

The drawings illustrate specific embodiments of the invention, which are explained in greater detail below.

FIG. 1 shows a modular view of the entire production line with the individual units.

FIG. 2 shows a block diagram of a production line with a combination based on local conditions that consists of a continuous strip casting installation with a milling installation.

FIG. 3 shows a block diagram of a production line with a combination that consists of a continuous strip casting installation/milling installation/reversing mill.

FIG. 4 shows a block diagram of a production line with a combination that consists of a continuous strip casting installation/milling installation/and tandem mill.

FIG. 5 shows a block diagram of a production line with a combination that consists of a continuous strip casting installation/milling installation and tandem mill.

FIG. 6 shows a block diagram of a production line with two parallel continuous strip casting installations, each of which is combined with a milling installation, and a tandem mill.

FIG. 7 shows a block diagram of a production line with one vertical and one horizontal continuous strip casting installation, each of which is immediately followed by a milling installation, and a tandem mill.

FIG. 8 shows a block diagram of a production line with parallel vertical continuous strip casting installations, followed by parallel milling installations and parallel reversing mills.

FIG. 9 shows a production line with a parallel pair of vertical and horizontal continuous strip casting installations, each of which is followed by a reversing mill.

To produce a metal strip 1 from a soft material (FIG. 1), molten metal 2, e.g., copper or a copper alloy, is cast from a melting furnace (not shown in detail) in a continuous strip casting process, and the copper strip 4 is descaled by milling 5 with support rollers arranged obliquely opposite each other on the upper side 5 a and the underside 5 b of the copper strip 4, subjected to a cold rolling process 6, subjected to a surface inspection 12, coiled into a coil 13, and then prepared for shipment.

A coil 13 can also be returned to the cold rolling process 6 for further reduction of the thickness 18 of the copper strip. The microstructure, which is thus very strongly compressed, is coiled into an inspected coil in a treatment by annealing 7, pickling 8, washing 9, drying 10 and possibly a temper rolling step 11, followed by an inspection 12.

Stacked sheets 14 are then produced from the coils 13, whose surfaces have been inspected, by cutting the copper strip 4 to length. The sheets are then sent for shipment. Alternatively, coilable narrow copper strips 17 are produced from the inspected coils 13 by slitting 16 the copper strip and are then sent for shipment (in the arrow direction).

To produce a desired microstructure and analogous properties for the protection of the work rolls, the cold rolling process 6 can be carried out in such a way that the copper strip 4 is lubricated with oil on the run-in side (FIG. 1, left) or cooled and cleaned with cold or cryogenic inert gases, e.g., nitrogen, on the runout side (FIG. 1, right). The set points for the rolling parameters are set to a maximum strip temperature of 120° C. on the runout side.

The final strip thickness 18 is obtained under temperature control on the basis of an advantageous process of this type, and the coils 13 of copper strip are treated either in a box annealing installation 31 with the strip in coil form 13 (upper part of FIG. 1) or by a continuous annealing process 7 in order to refine the microstructure and to make the copper strip soft again. This is followed by pickling 8, washing 9, drying 10, and coiling into coils 13 that have been subjected to a surface inspection 12.

A melting installation 20 (e.g., an electric furnace) supplies melt to a casting installation 21, which consists of a vertical continuous strip casting installation 24 a or may also consist of a horizontal continuous strip casting installation 24 b in special cases or in cases in which such an installation is already present.

Cold deformation from 23 mm to 0.2 mm copper strip thickness 18 preferably takes place in a rolling installation 22 immediately downstream of the casting installation 21 and the milling 5.

The melting installation 20 is followed in succession in the direction of production 23 by at least the vertical continuous strip casting installation 24 a or in exceptional cases an existing horizontal continuous strip casting installation 24 b, an immediately downstream milling installation 25, a strip uncoiler 26, the cold rolling installation 22, a strip coiler 27, and an annealing installation 28, all of which are arranged in succession in the direction of production 23.

In the embodiment illustrated in FIG. 2, the cold rolling installation 22 is a reversing mill 29. It is an essential part of the invention that the milling installation 25 immediately follows the vertical continuous strip casting installation 24 a (or the horizontal continuous strip casting installation 24 b). The milling installation 25 is followed by a reversing mill 29, the box annealing installation 31, a strip floating furnace 32 a, together with the temper rolling step 11 and, if desired, a step in which the strip is cut to length 15 with a flying shear and in which the strip is slit 16 into narrow copper strips.

In the production line according to FIG. 3, the vertical continuous strip casting installation 24 a, the milling installation 25, and the reversing mill 29 form a functionally interacting unit.

In FIG. 4, the cold rolling unit 22 consists of a tandem mill 30. The milling installation 25 again follows directly after the vertical continuous strip casting installation 24 a.

In accordance with FIG. 5, which illustrates an arrangement similar to that of FIG. 3, the vertical continuous strip casting installation 24 a, the milling installation 25, and now a tandem mill 30 form the interacting unit. The box annealing installation 31, the strip floating furnace 32 a, the temper rolling step 11, and possibly the cutting to length 15 and/or the slitting 16 follow this unit in the same way as in the preceding FIGS. 2 to 4.

In FIG. 6, the casting capacity is increased. To this end, two parallel upstream vertical continuous strip casting installations 24 a, 24 a and their associated milling installations 25 are assigned to the tandem mill 30.

According to FIG. 7, one vertical continuous strip casting installation 24 a and one horizontal continuous strip casting installation 24 b, each with its own functionally connected milling installation 25, are arranged upstream of the tandem mill 30.

In FIG. 8, two parallel vertical continuous strip casting installations 24 a, 24 a and their respective milling installations 25 are each followed by a reversing mill 29 at a customary fixed distance.

FIG. 9 shows an arrangement in which vertical and horizontal continuous strip casting installations 24 a, 24 b in parallel production are each followed at the customary distance by a reversing mill 29.

The annealing installation 28 consists either of a box annealing installation 31 for coils 13 or a continuous annealing installation 32 in the form of a strip floating furnace 32 a.

LIST OF REFERENCE NUMBERS

-   1 metal strip -   2 melt -   3 continuous strip casting process -   4 copper strip -   5 milling -   5 a upper side of the metal strip -   5 b underside of the metal strip -   6 cold rolling process -   7 annealing -   8 pickling -   9 washing -   10 drying -   11 temper rolling step -   12 inspection -   13 (inspected) coil -   14 sheets -   15 cutting to length -   16 slitting -   17 narrow copper strips -   18 copper strip thickness -   19 -   20 melting installation -   21 casting installation -   22 (cold) rolling installation -   23 direction of production -   24 a vertical continuous strip casting installation -   24 b horizontal continuous strip casting installation -   25 milling installation -   26 strip uncoiler -   27 strip coiler -   28 annealing installation -   29 reversing mill -   30 tandem mill -   31 box annealing installation -   32 continuous annealing installation -   32 a strip floating furnace 

1. A method for producing metal strip (1) from copper or copper alloys by casting and rolling, wherein the melt (2) is cast into copper strip (4) in a vertical and/or horizontal continuous strip casting process (3) and that the copper strip (4) is cleaned by milling (5) its upper side (5 a) and underside (5 b), subjected to a cold rolling process (6), and prepared for shipment, or the copper strip (4) is first annealed (7), pickled (8), washed (9), and dried (10), possibly subjected to a temper rolling step (11), and then inspected and prepared for shipment.
 2. A method in accordance with claim 1, wherein stacks of sheets (14) are produced from inspected coils (13) by cutting (15) the copper strip (4) to length.
 3. A method in accordance with claim 1, wherein coilable narrow copper strips (17) are produced from inspected coils (13) by slitting (16) the copper strip (4).
 4. A method in accordance with claim 1, wherein during cold rolling (6), the copper strip (4) is lubricated with oil on the run-in side and cooled with cold or cryogenic inert gases on the runout side.
 5. A method in accordance with claim 1, wherein the set-point assignment for the rolling parameters is set to a maximum strip temperature of 120° C.
 6. A method in accordance with claim 1, wherein the coils (13) of copper strip that have been cold rolled under temperature control to final strip thickness (18) are refined in their microstructure either in a box annealing installation (31) in the form of a coil (13) or in a continuous annealing operation (7) and then pickled, washed and dried, subjected to a surface inspection, and then further processed in coil form (13).
 7. A production line for producing metal strip (1) from copper or copper alloy with at least a melting installation (20), a casting installation (21), and a rolling installation (22), preferably for cold forming from 23 mm to 0.2 mm copper strip thickness (18), wherein the melting installation (20) is followed in succession in the direction of production (23) by at least one vertical continuous strip casting installation (24 a) and/or one horizontal continuous strip casting installation (24 b), a milling installation (25) immediately downstream, a strip uncoiler (26), a cold rolling installation (22), a strip coiler (27), and an annealing installation (28).
 8. A production line in accordance with claim 7, wherein the cold rolling installation (22) consists of a reversing mill (29).
 9. A production line in accordance with claim 8, wherein the milling installation (25) is located immediately downstream of the vertical continuous strip casting installation (24 a).
 10. A production line in accordance with claim 7, wherein the vertical continuous strip casting installation (24 a), the milling installation (25), and the reversing mill (29) follow one another in immediate succession.
 11. A production line in accordance with claim 7, wherein the cold rolling installation (22) consists of a tandem mill (30).
 12. A production line in accordance with claim 7, wherein the vertical continuous strip casting installation (24 a), the milling installation (25), and the tandem mill (30) follow one another in immediate succession.
 13. A production line in accordance with claim 7, wherein two parallel upstream vertical continuous strip casting installations (24 a; 24 a) and milling installations (25) are assigned to the tandem mill (30).
 14. A production line in accordance with claim 7, wherein one vertical and one horizontal continuous strip casting installation (24 a; 24 b), each with a milling installation (25) installed immediately downstream of it, are installed upstream of the tandem mill (30).
 15. A production line in accordance with claim 7, wherein with two parallel-casting vertical continuous strip casting installations (24 a; 24 a), a reversing mill (29) follows each milling installation (25).
 16. A production line in accordance with claim 7, wherein parallel-producing vertical and horizontal continuous strip casting installations (24 a; 24 b) are each followed by a reversing mill (29).
 17. A production line in accordance with claim 7, wherein the annealing installation (28) consists either of a box annealing installation (31) for coils (13) or of a continuous annealing installation (32) in the form of a strip floating furnace (32 a). 